Apparatus for Treating Crankcase Gases from Engines

ABSTRACT

Apparatus is provided for removing oil from crankcase gases flowing from an internal combustion engine. The apparatus includes filtration particles, contained within an outer case, that collect oil particles and allow drainage of the oil into an accumulator. An inner shell may be used as a water accumulator.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates generally to internal combustion engines,and specifically to separation of oil from crankcase gases of internalcombustion engines.

2. Description of Related Art

in automobile racing, and especially in the sport of drag racing,horsepower is very important. Drag races are often decided bythousandths of a second. Even small gains in engine efficiency can leadto victory. One well known method of increasing engine efficiency in theart of engine building is to run a vacuum pump on the crankcase side ofthe engine. Crankcase gases are often evacuated to a “breather,” whichis typically a reservoir with a fiber-based filter element on top.Although these vacuum systems are successful in increasing horsepower,oil particles are typically exhausted from the “breather” at a highrate. This condition pollutes, creates a fire risk, and causes unsafeconditions on race tracks. Because of the way current systems aredesigned, an oil mist accumulates in the engine compartment (on theengine, underside of the hood and firewall). One of the most annoyingresponsibilities of a crew chief for drag racing is cleaning the enginecompartment between races. If not cleaned between races, thisaccumulated oil can cause a fire hazard.

The most common vacuum systems for internal combustion engines are beltdriven centrifugal pumps. These pumps are typically driven by thecrankshaft. They draw crankcase gases from fittings on valve covers orfrom the oil valley. The gases are a mixture of the products ofcombustion that flow past the pistons (“blow-by gases”) and air filledwith atomized oil particles created by the rotating action of thecrankshaft. Although these systems add weight to a vehicle, in dragracing the net increase in horsepower is thought to offset theundesirable effect of the additional weight. State-of-the-art vacuumsystems are commercially available from Aerospace Components of St.Petersburg, Fla. and Moroso of Guilford, Conn., for example.

Water-cooled engines also need overflow volume for expansion of fluid inthe cooling system as the engine heats. This is normally a separateaccumulator system on a race car. It requires a second mounting area,extra weight, and reduces the amount of space in the engine compartmentarea. Current systems on racecars have several parts that work togetherin an attempt to separate air, oil and water. These include: an oil/airseparator prior to the vacuum pump, an atmospheric air volume regulator(pressure regulator) prior to the vacuum pump, an oil accumulator tank,a breather filter on top of the oil accumulator, and a water accumulatorfor overflow.

The need for oil-air separators has been felt since the advent of theinternal combustion engine. U.S. Pat. No. 973,118, dated Oct. 18, 1910,discloses an apparatus that draws gases out of the crankcase, andrecycles those gases into the intake of the cylinders. This early formof the oil-air separator took the form of “a pipe . . . to maintain theair free of oil or dirt . . . . ”

U.S. Pat. No. 5,063,882, titled “Oil Separation for Gases from aCrankcase of an Internal Combustion Engine,” to Dr. Ing.h.c.F. Porsche.Aktiengesellschaft discloses an oil separator based on a labyrinthcomprising two deceleration paths for oil contained in crankcase gases.

U.S. Pat. No. 6,167,849 discloses an oil collector particularly adaptedto motorcycles. It is said to cool blow-by gases containing oil vaporand particles and then to discharge the gases to the atmosphere througha filter, which is not described, but appears to be conventional pleatedair filter.

U.S. Patent Application Publication No. 2008/0047505 A1, titled “OilSeparator Element,” discloses an oil separator element that operates bysetting crankcase gases in rotational motion so that centrifugal forcescause oil droplets to form on the walls of the grooves in the filterelement.

What is needed, especially for race cars, is a system that combines theoil/air/water separation into one unit. Not only could this systemeliminate the need for all the separate systems listed above, it wouldalso reduce the weight of the car (each piece above plus all theirbrackets, clamps). With only one unit (compared to six separate pieces)required to accomplish the tasks, adjustments and replacements wouldalso be much simpler. For race cars, and for crankcase gases from allinternal combustion engines, including those in all vehicles andstationary engines, there is a need for a more effective, economicalapparatus to separate the oil in crankcase gases from the gas phase andaccumulate the separated oil.

BRIEF SUMMARY OF THE INVENTION

The problem of efficiently separating oil from crankcase gases isprovided by a combination of centrifugal force, cooling of a surface anda filter made by a bed of particles. A canister for use in race cars isprovided by concentric accumulators for water and oil, with the bed ofparticles collecting oil so that it drains into the oil accumulator. Aline for returning separated oil to the engine may be provided, withflow in the line being by pressure control or level control in the oilaccumulator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is an elevation view of one embodiment of the device disclosedherein attached to the crankcase gas vacuum system and the coolingsystem of an engine.

FIG. 2 is a cross-sectional view of one embodiment of the air-oilseparator and liquid accumulator disclosed herein.

FIG. 3 is a perspective view of a filter support for particles in theair-oil separator.

FIG. 4 is a perspective view of one embodiment of a particle for thefilter.

FIG. 5 is a perspective view of another embodiment of a particle for thefilter.

FIG. 6 is a cross-sectional perspective view of the lower base of oneembodiment of the air-oil separator and liquid accumulator disclosedherein.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, oil-air separator/accumulator 17 installed in theengine compartment of an automobile is illustrated. Also shown is vacuumpump 16, which is connected to oil valley cover 15 for removingcrankcase gases from engine block 10 through hose 16A. Vacuum pump 16may not be used, and separator/accumulator 17 may be connected directlyto oil valley cover 15 or any other location on the engine for ventingcrankcase gases. Power for vacuum pump 16 is taken through belt 16D fromcrankshaft pulley 11. Intake manifold 13 feeds fuel and air fromcarburetor 13A. Alternatively, electronic fuel injection can deliverfuel and air to intake manifold 13. Exhaust header 14 evacuates productsof combustion from the cylinders of engine block 10.

Separator/accumulator 17 may be connected to radiator 19 through hose19B, in which case separator/accumulator 17 may serve also as overflowaccumulator for radiator 19. Water drain valve 17D may be opened toremove accumulated water. A tube connected to radiator 19 may extendinto the water accumulator.

Oil may be drained from separator/accumulator 17 through oil drain valve17C, in which case valve 17C has a drain tube as shown attached to valve17D, into a separate container. Alternatively, oil drain valve 17C maybe always open and connected by hose to valve 17E. Oil may then flowthrough valve 17E and return to valve cover 12 through hose 18. Hose 18may be attached to the engine in any low-pressure location to return oilto the lubrication system. Oil pan/crankcase 18 is the main lubricatingoil reservoir for the engine.

The reasons to automatically return the separated oil back to the enginethrough hoses and valve 17E depend on the environment and use of theengine. In drag racing, after every race the oil is usually drained intoa cup or bowl and then discarded. Racing oil is expensive, soautomatically returning the oil to the engine will save time and money.For engines running long times or continuously, including engines inautomobiles, motorcycles, piston-driven aircraft (where a “wet belly” iscommon), circuit racing engines (all types), and industrial machines andequipment, returning oil to the engine will reduce air pollution ascompared with burning it via the intake system of the engine orotherwise disposing of the oil.

Valve 17E may be a check valve supplied by Smart Products of MorganHill, Calif. It may be designed to open at selected pressures, forexample, in the range of 1-3 psi. Opening pressure may be selected byobserving operation of the accumulator/separator on an engine.Alternatively, check valve 17E may be a valve controlled by the oillevel in separator/accumulator 17. Valves controlled by a fluid level ina container are well known in industry. Electrical signals may be usedto control the opening and closing of valve 17E.

Crankshaft pulley 11 may rotate up to about 10,000-11,000 RPM, dependingon engine design. Vacuum provided by vacuum pump 16 varies, and mayreach an absolute pressure of about 18 to 20 in Hg when the engine isoperating at high RPM. Discharge pressure from pump 16 is preferablyjust slightly above atmospheric pressure, so that lower intake pressurewill be possible. Discharge pressure will be determined by pressure lossacross separator/accumulator 17. Crankcase gas after removal of oil isdischarged from the top of separator/accumulator 17.

Separator/accumulator 17 is preferably mounted in the engine compartmentin a location where outside air contacts the surface to afford as muchcooling of the surface as possible to maximize condensation of any oilvapor in the separator.

Referring to FIG. 2, a preferred embodiment of separator/accumulator 17is illustrated. Crankcase gas inlet port 21 may be perpendicular to thesurface of outer shell 20 or may be oriented at an angle to outer shell20 to facilitate centrifugal force on particles in the incoming gas.Volume 26 is formed by lower base 23, inner shell 24 and outer shell 20,and functions as an oil accumulator.

Base 23 is a cylindrical cup forming the bottom of separator/accumulator17. A detailed cut away perspective view of base 23 is shown in FIG. 6.Outer shell retainer 60 is a cylindrical wall. The outer surface ofouter shell retainer 60 has o-ring grooves 64, adapted for o-ring seals63. Shoulder 67 acts as a seat for outer shell 20. Inside outer shellretainer 60 is inner shell retainer 61, with threads 62 on the innersurface of inner shell retainer 61, formed so as to accept the malethreads of inner shell 24 (FIG. 2). The bottom of lower base 23 has oiloutlet port 65 and water outlet port 66.

Top end piece 25 (FIG. 2) is also a cylindrical cup, and has the sameoutside and inside dimensions as base 23. Water inlet port 25A may belocated at the center of top end piece 25. In the event of greatervolume of water overflow than volume 29, port 25C may provide pressurerelief. Air outlet ports 25B discharge cleaned gas fromseparator/accumulator 17. O-rings 63 seal top end piece 25 to outershell 20. The outer casing of separator/accumulator 17 is formed by topend piece 25, outer shell 20 and base 23.

Oil-gas separation begins in volume 26, where oil particles impinge onthe surfaces. The gas stream then flows through filter section 27 andexhausts through volume 28 to the atmosphere. Filter section 27 may havelower filter particle layer 27A, middle filter particle layer 27B, upperfilter particle layer 27C, and filter supports 30. Ports 31 in filtersupport 30 are sized to retain filter particles. Lower filter particlelayer 27A may contain a selected amount of smaller filter particles 50.Middle filter particle layer 27B may contain a selected amount of largercylindrical filter particle 40. Upper filter particle layer 27C may alsocontain smaller filter particles 50. Alternatively, the particles ineach layer may be of the same size or any combination of sizes. A rangeof particle sizes may be placed in each layer. In a preferredembodiment, there is a gap between inner shell 24 and inner diameter 52of filter supports 30 to allow oil to drain down inner shell 24.

Referring to FIG. 3, perforated filter support 30 is illustrated. In apreferred embodiment, two filter supports 30 are identical. Preferably,the outer diameter of filter support 30 is approximately equal to theinner diameter of outer shell 20 such that filter support 30 may bepressed into outer shell 20 and held in place inside outer shell 20without a retainer. Filter support 30 has ports 31 through its surface.Inner diameter 32 is preferably formed to allow a gap between filtersupport 30 and inner shell 24.

Referring to FIG. 4, cylindrical filter particle 40 is illustrated,having cylindrical outer surface 41 and channel 42 through the particle.In a preferred embodiment, particle 40 is made of polymer having a highmelting point and oil resistance, such as polyethylene, polypropylene,polystyrene, Teflon, or other polymers. Alternatively, filter particle40 may be made of metal, or any other heat and oil resistant material.Particle 40 may be selected from particles from about 1/16 in diameterand length to about ⅜ in diameter and length. A preferred diameter andlength is about 3/16 with a channel diameter of about ⅛ in. Particle 40preferably has high surface area and sufficient size to cause lowpressure drop across a bed of particles.

Referring to FIG. 5, spheroid filter particle 50 is illustrated, havingouter surface 51, conical end surface 52, and cylindrical channel 53through the filter particle. In a preferred embodiment, spheroid filterparticle 50 may have a composition and size as described for particle40.

To assemble device 17, press fit lower filter support 30 into outershell 20, as shown in FIG. 2. Screw inner shell 24 into inner shellretainer 61 of base 23. Seat seals 63 into grooves 64 of lower base 23(FIG. 6). Press fit base 23 into outer shell 20. Add lower filterparticle layer 27A, add middle filter particle layer 27B, then add upperfilter particle layer 27C. Smaller particles may be used in one layer,as shown in FIG. 2. Any combination of particle sizes may be used, asdescribed above. Press fit filter support 30 so as to contact upperfilter particle layer 27C. Seat seals 63 into grooves 64 of top endpiece 25. Screw upper end piece 25 onto threads of inner shell 24. Thedevice may then be mounted and connected to an engine as shown inFIG. 1. The device may be used for air-oil separation only, in whichcase the connections to a radiator would not be made.

In volume 27, as gas containing oil droplets flows through the filter,oil impacts and wets the filter particles. Oil then drains downwardthrough the filter particles. The individual filter particles preferablyhave a large surface area for wetting and for oil drainage. Channelsthrough the particles, such as shown in FIG. 4 and 5, are believed toallow greater rate of oil drainage. In all cases, the particles may haveonly one size or may be made up of intermixed particles. The particlesmay have one or more channels though the particles. The length of thebed of filter particles is preferably in the range from about ⅙ to about⅚ of the distance from gas inlet port 21 to outlet ports 25B.

Apparatus 17 may be constructed in a wide range of sizes, depending onthe engine on which it will be used and the conditions of use. The sizeof accumulator selected will vary depending on when and how accumulatedliquid is to be removed. For example, for a race car for drag racing,outer shell 20 may have an outer diameter of 4 in, an inner diameter of3⅞ in and a length of 11.5 in. Inlet port 21 may be ⅝ in diameter withcenter point 3¼ in from the bottom of outer shell 20. Inner shell 24 mayhave an outside diameter of 2 in. Ports 31, 25B and 25C may be about0.09 inches in diameter.

The separator/accumulator of FIG. 2 was placed on a 750 HP racecarduring drag races and used under actual race conditions. The enginecompartment showed no evidence of oil coating surfaces after a race.Testing consistently resulted in an oil-free system that separated theoil/air/water without an oil/air separator accumulator tank and an airbreather and internal baffle.

A test was also performed while a race shop was “dynoing” a customer's1000+ HP engine. The race shop was using a standard system with internalbaffles, which was releasing oil despite all attempts to correct it. Theapparatus disclosed here was installed without any internal baffling.The water overflow was connected, the engineer made a pull on the dyno,and oil-free oil/air/water separation was observed.

Although the present invention has been described with respect tospecific details, it is not intended that such details should beregarded as limitations on the scope of the invention, except to theextent that they are included in the accompanying claims.

1) An apparatus for separation of oil from crankcase gases of an engine,comprising: an outer casing having a gas inlet and a gas outlet; aninner shell; a filter support interposed between the gas inlet and gasoutlet; a selected volume of filtering particles of a selected sizerange interposed between the filter support and the gas outlet; and aport for oil flow from the outer casing. 2) The apparatus of claim 1,wherein the filtering particles comprise a polymer. 3) The apparatus ofclaim 1, wherein the filtering particles contain channels therein forfluid flow. 4) The apparatus of claim 1, wherein the volume of filteringparticles comprises a plurality of layers, each of a selected size. 5)The apparatus of claim 1, further comprising an inlet port and an outletport in the inner shell. 6) The apparatus of claim 1, further comprisinga flow line for returning oil to the engine. 7) The apparatus of claim6, further comprising a valve in the flow line. 8) A method forseparating oil from crankcase gases of an engine, comprising: providingthe apparatus of claim 1; providing a first conduit from a region of theengine containing crankcase gases; connecting the first conduit to theapparatus of claim 1; and operating the engine. 9) The method of claim8, further comprising: adding an inlet port and outer port within theinner shell; providing a second conduit from a radiator; and connectingthe second conduit to the inlet port within the inner shell. 10) Themethod of claim 8, further comprising; providing a conduit between theport for oil flow in the outer casing and the engine; and returning oilto the engine. 11) The method of claim 10 further comprising placing acheck valve in the conduit. 12) The method of claim 10 furthercomprising placing a valve in the conduit and operating the valve inresponse to oil level in the accumulator.